A source close to Fox told the PA news agency it had been a "very difficult period for him and his family".

Equity apologised in a statement, saying "it did not intend to suggest that the actor should be denied the ability to work".

The union announced on Twitter: "We are sorry that in the tweets he was called a 'disgrace' by Equity.

"It was a mistake for Equity as an organisation to criticise him in this way.

On 17 January a series of tweets were posted by the @EquityMEM Twitter account about Laurence Fox's appearance on BBC Question Time. We are sorry that in the tweets he was called a 'disgrace' by Equity. Please read Equity's full statement. https://t.co/NlW8f88iRspic.twitter.com/5zgbG5623d

"Equity and Laurence Fox can issue as many joint statements and apologies as they like. It's nothing to do with me and I apologise for nothing #NotInMyName," he wrote on Twitter.

The committee said that "all members of Equity's recently renamed Race Equality Committee (formerly the Equity Minority Ethnic Members Committee) feel we have no choice but to resign as committee members".

Fox sparked controversy when he responded to a claim from an audience member that the media's treatment of the Duchess of Sussex amounted to "racism".

"It's not racism ... we're the most tolerant, lovely country in Europe," the star, part of the Fox acting dynasty, said.

"It's so easy to throw the charge of racism and it's really starting to get boring now."

The audience member then described Fox as a "white, privileged male", to which he responded: "To call me a white, privileged male is to be racist."

The episode received more than 250 complaints and sparked a social media backlash, which Fox called "water off a duck's back".

Fox, who was previously married to actress Billie Piper, said he had received death threats and had suffered from "temporary insomnia" after his appearance.

He later hit out at black and working-class actors for complaining about the industry once they have "five million quid in the bank" before saying he was signing off Twitter because "I have to turn this noise off for a while".